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<a href="g711_8h.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="comment">/*</span></div>
<div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="comment"> * SpanDSP - a series of DSP components for telephony</span></div>
<div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment"> * g711.h - In line A-law and u-law conversion routines</span></div>
<div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment"> * Written by Steve Underwood &lt;steveu@coppice.org&gt;</span></div>
<div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="comment"> * Copyright (C) 2001 Steve Underwood</span></div>
<div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="comment"> *  Despite my general liking of the GPL, I place this code in the</span></div>
<div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="comment"> *  public domain for the benefit of all mankind - even the slimy</span></div>
<div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160;<span class="comment"> *  ones who might try to proprietize my work and use it to my</span></div>
<div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="comment"> *  detriment.</span></div>
<div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160;</div>
<div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="comment">/* g711_page A-law and mu-law handling</span></div>
<div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="comment">Lookup tables for A-law and u-law look attractive, until you consider the impact</span></div>
<div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="comment">on the CPU cache. If it causes a substantial area of your processor cache to get</span></div>
<div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;<span class="comment">hit too often, cache sloshing will severely slow things down. The main reason</span></div>
<div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;<span class="comment">these routines are slow in C, is the lack of direct access to the CPU&#39;s &quot;find</span></div>
<div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;<span class="comment">the first 1&quot; instruction. A little in-line assembler fixes that, and the</span></div>
<div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;<span class="comment">conversion routines can be faster than lookup tables, in most real world usage.</span></div>
<div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;<span class="comment">A &quot;find the first 1&quot; instruction is available on most modern CPUs, and is a</span></div>
<div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160;<span class="comment">much underused feature. </span></div>
<div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;<span class="comment">If an assembly language method of bit searching is not available, these routines</span></div>
<div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160;<span class="comment">revert to a method that can be a little slow, so the cache thrashing might not</span></div>
<div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;<span class="comment">seem so bad :(</span></div>
<div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;<span class="comment">Feel free to submit patches to add fast &quot;find the first 1&quot; support for your own</span></div>
<div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;<span class="comment">favourite processor.</span></div>
<div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160;<span class="comment">Look up tables are used for transcoding between A-law and u-law, since it is</span></div>
<div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;<span class="comment">difficult to achieve the precise transcoding procedure laid down in the G.711</span></div>
<div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;<span class="comment">specification by other means.</span></div>
<div class="line"><a name="l00037"></a><span class="lineno">   37</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160;</div>
<div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160;<span class="preprocessor">#ifndef MPF_G711_H</span></div>
<div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;<span class="preprocessor"></span><span class="preprocessor">#define MPF_G711_H</span></div>
<div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;<span class="preprocessor"></span><span class="comment"></span></div>
<div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;<span class="comment">/**</span></div>
<div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;<span class="comment"> * @file g711.h</span></div>
<div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;<span class="comment"> * @brief A-law and u-law conversion routines</span></div>
<div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160;<span class="comment"> */</span> </div>
<div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;</div>
<div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;<span class="preprocessor">#include &quot;<a class="code" href="mpf_8h.html">mpf.h</a>&quot;</span></div>
<div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;</div>
<div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;<a class="code" href="apt_8h.html#ad3d792bfc75893affad257781ea46e55">APT_BEGIN_EXTERN_C</a></div>
<div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160;</div>
<div class="line"><a name="l00051"></a><span class="lineno">   51</span>&#160;<span class="preprocessor">#if defined(__i386__)</span></div>
<div class="line"><a name="l00052"></a><span class="lineno">   52</span>&#160;<span class="preprocessor"></span><span class="comment">/*! \brief Find the bit position of the highest set bit in a word</span></div>
<div class="line"><a name="l00053"></a><span class="lineno">   53</span>&#160;<span class="comment">    \param bits The word to be searched</span></div>
<div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;<span class="comment">    \return The bit number of the highest set bit, or -1 if the word is zero. */</span></div>
<div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160;<span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> top_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;{</div>
<div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;    <span class="keywordtype">int</span> res;</div>
<div class="line"><a name="l00058"></a><span class="lineno">   58</span>&#160;</div>
<div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160;    __asm__ __volatile__(<span class="stringliteral">&quot; movl $-1,%%edx;\n&quot;</span></div>
<div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;                         <span class="stringliteral">&quot; bsrl %%eax,%%edx;\n&quot;</span></div>
<div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;                         : <span class="stringliteral">&quot;=d&quot;</span> (res)</div>
<div class="line"><a name="l00062"></a><span class="lineno">   62</span>&#160;                         : <span class="stringliteral">&quot;a&quot;</span> (bits));</div>
<div class="line"><a name="l00063"></a><span class="lineno">   63</span>&#160;    <span class="keywordflow">return</span> res;</div>
<div class="line"><a name="l00064"></a><span class="lineno">   64</span>&#160;}</div>
<div class="line"><a name="l00065"></a><span class="lineno">   65</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00067"></a><span class="lineno">   67</span>&#160;<span class="comment">/*! \brief Find the bit position of the lowest set bit in a word</span></div>
<div class="line"><a name="l00068"></a><span class="lineno">   68</span>&#160;<span class="comment">    \param bits The word to be searched</span></div>
<div class="line"><a name="l00069"></a><span class="lineno">   69</span>&#160;<span class="comment">    \return The bit number of the lowest set bit, or -1 if the word is zero. */</span></div>
<div class="line"><a name="l00070"></a><span class="lineno">   70</span>&#160;<span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> bottom_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;{</div>
<div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160;    <span class="keywordtype">int</span> res;</div>
<div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;</div>
<div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;    __asm__ __volatile__(<span class="stringliteral">&quot; movl $-1,%%edx;\n&quot;</span></div>
<div class="line"><a name="l00075"></a><span class="lineno">   75</span>&#160;                         <span class="stringliteral">&quot; bsfl %%eax,%%edx;\n&quot;</span></div>
<div class="line"><a name="l00076"></a><span class="lineno">   76</span>&#160;                         : <span class="stringliteral">&quot;=d&quot;</span> (res)</div>
<div class="line"><a name="l00077"></a><span class="lineno">   77</span>&#160;                         : <span class="stringliteral">&quot;a&quot;</span> (bits));</div>
<div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;    <span class="keywordflow">return</span> res;</div>
<div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;}</div>
<div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00081"></a><span class="lineno">   81</span>&#160;<span class="preprocessor">#elif defined(__x86_64__)</span></div>
<div class="line"><a name="l00082"></a><span class="lineno">   82</span>&#160;<span class="preprocessor"></span><span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> top_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00083"></a><span class="lineno">   83</span>&#160;{</div>
<div class="line"><a name="l00084"></a><span class="lineno">   84</span>&#160;    <span class="keywordtype">int</span> res;</div>
<div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160;</div>
<div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160;    __asm__ __volatile__(<span class="stringliteral">&quot; movq $-1,%%rdx;\n&quot;</span></div>
<div class="line"><a name="l00087"></a><span class="lineno">   87</span>&#160;                         <span class="stringliteral">&quot; bsrq %%rax,%%rdx;\n&quot;</span></div>
<div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;                         : <span class="stringliteral">&quot;=d&quot;</span> (res)</div>
<div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;                         : <span class="stringliteral">&quot;a&quot;</span> (bits));</div>
<div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;    <span class="keywordflow">return</span> res;</div>
<div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;}</div>
<div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;</div>
<div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;<span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> bottom_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;{</div>
<div class="line"><a name="l00096"></a><span class="lineno">   96</span>&#160;    <span class="keywordtype">int</span> res;</div>
<div class="line"><a name="l00097"></a><span class="lineno">   97</span>&#160;</div>
<div class="line"><a name="l00098"></a><span class="lineno">   98</span>&#160;    __asm__ __volatile__(<span class="stringliteral">&quot; movq $-1,%%rdx;\n&quot;</span></div>
<div class="line"><a name="l00099"></a><span class="lineno">   99</span>&#160;                         <span class="stringliteral">&quot; bsfq %%rax,%%rdx;\n&quot;</span></div>
<div class="line"><a name="l00100"></a><span class="lineno">  100</span>&#160;                         : <span class="stringliteral">&quot;=d&quot;</span> (res)</div>
<div class="line"><a name="l00101"></a><span class="lineno">  101</span>&#160;                         : <span class="stringliteral">&quot;a&quot;</span> (bits));</div>
<div class="line"><a name="l00102"></a><span class="lineno">  102</span>&#160;    <span class="keywordflow">return</span> res;</div>
<div class="line"><a name="l00103"></a><span class="lineno">  103</span>&#160;}</div>
<div class="line"><a name="l00104"></a><span class="lineno">  104</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00105"></a><span class="lineno">  105</span>&#160;<span class="preprocessor">#else</span></div>
<div class="line"><a name="l00106"></a><span class="lineno">  106</span>&#160;<span class="preprocessor"></span><span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> top_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00107"></a><span class="lineno">  107</span>&#160;{</div>
<div class="line"><a name="l00108"></a><span class="lineno">  108</span>&#160;    <span class="keywordtype">int</span> i;</div>
<div class="line"><a name="l00109"></a><span class="lineno">  109</span>&#160;    </div>
<div class="line"><a name="l00110"></a><span class="lineno">  110</span>&#160;    <span class="keywordflow">if</span> (bits == 0)</div>
<div class="line"><a name="l00111"></a><span class="lineno">  111</span>&#160;        <span class="keywordflow">return</span> -1;</div>
<div class="line"><a name="l00112"></a><span class="lineno">  112</span>&#160;    i = 0;</div>
<div class="line"><a name="l00113"></a><span class="lineno">  113</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0xFFFF0000)</div>
<div class="line"><a name="l00114"></a><span class="lineno">  114</span>&#160;    {</div>
<div class="line"><a name="l00115"></a><span class="lineno">  115</span>&#160;        bits &amp;= 0xFFFF0000;</div>
<div class="line"><a name="l00116"></a><span class="lineno">  116</span>&#160;        i += 16;</div>
<div class="line"><a name="l00117"></a><span class="lineno">  117</span>&#160;    }</div>
<div class="line"><a name="l00118"></a><span class="lineno">  118</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0xFF00FF00)</div>
<div class="line"><a name="l00119"></a><span class="lineno">  119</span>&#160;    {</div>
<div class="line"><a name="l00120"></a><span class="lineno">  120</span>&#160;        bits &amp;= 0xFF00FF00;</div>
<div class="line"><a name="l00121"></a><span class="lineno">  121</span>&#160;        i += 8;</div>
<div class="line"><a name="l00122"></a><span class="lineno">  122</span>&#160;    }</div>
<div class="line"><a name="l00123"></a><span class="lineno">  123</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0xF0F0F0F0)</div>
<div class="line"><a name="l00124"></a><span class="lineno">  124</span>&#160;    {</div>
<div class="line"><a name="l00125"></a><span class="lineno">  125</span>&#160;        bits &amp;= 0xF0F0F0F0;</div>
<div class="line"><a name="l00126"></a><span class="lineno">  126</span>&#160;        i += 4;</div>
<div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160;    }</div>
<div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0xCCCCCCCC)</div>
<div class="line"><a name="l00129"></a><span class="lineno">  129</span>&#160;    {</div>
<div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160;        bits &amp;= 0xCCCCCCCC;</div>
<div class="line"><a name="l00131"></a><span class="lineno">  131</span>&#160;        i += 2;</div>
<div class="line"><a name="l00132"></a><span class="lineno">  132</span>&#160;    }</div>
<div class="line"><a name="l00133"></a><span class="lineno">  133</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0xAAAAAAAA)</div>
<div class="line"><a name="l00134"></a><span class="lineno">  134</span>&#160;    {</div>
<div class="line"><a name="l00135"></a><span class="lineno">  135</span>&#160;        bits &amp;= 0xAAAAAAAA;</div>
<div class="line"><a name="l00136"></a><span class="lineno">  136</span>&#160;        i += 1;</div>
<div class="line"><a name="l00137"></a><span class="lineno">  137</span>&#160;    }</div>
<div class="line"><a name="l00138"></a><span class="lineno">  138</span>&#160;    <span class="keywordflow">return</span> i;</div>
<div class="line"><a name="l00139"></a><span class="lineno">  139</span>&#160;}</div>
<div class="line"><a name="l00140"></a><span class="lineno">  140</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00141"></a><span class="lineno">  141</span>&#160;</div>
<div class="line"><a name="l00142"></a><span class="lineno">  142</span>&#160;<span class="keyword">static</span> APR_INLINE <span class="keywordtype">int</span> bottom_bit(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> bits)</div>
<div class="line"><a name="l00143"></a><span class="lineno">  143</span>&#160;{</div>
<div class="line"><a name="l00144"></a><span class="lineno">  144</span>&#160;    <span class="keywordtype">int</span> i;</div>
<div class="line"><a name="l00145"></a><span class="lineno">  145</span>&#160;    </div>
<div class="line"><a name="l00146"></a><span class="lineno">  146</span>&#160;    <span class="keywordflow">if</span> (bits == 0)</div>
<div class="line"><a name="l00147"></a><span class="lineno">  147</span>&#160;        <span class="keywordflow">return</span> -1;</div>
<div class="line"><a name="l00148"></a><span class="lineno">  148</span>&#160;    i = 32;</div>
<div class="line"><a name="l00149"></a><span class="lineno">  149</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0x0000FFFF)</div>
<div class="line"><a name="l00150"></a><span class="lineno">  150</span>&#160;    {</div>
<div class="line"><a name="l00151"></a><span class="lineno">  151</span>&#160;        bits &amp;= 0x0000FFFF;</div>
<div class="line"><a name="l00152"></a><span class="lineno">  152</span>&#160;        i -= 16;</div>
<div class="line"><a name="l00153"></a><span class="lineno">  153</span>&#160;    }</div>
<div class="line"><a name="l00154"></a><span class="lineno">  154</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0x00FF00FF)</div>
<div class="line"><a name="l00155"></a><span class="lineno">  155</span>&#160;    {</div>
<div class="line"><a name="l00156"></a><span class="lineno">  156</span>&#160;        bits &amp;= 0x00FF00FF;</div>
<div class="line"><a name="l00157"></a><span class="lineno">  157</span>&#160;        i -= 8;</div>
<div class="line"><a name="l00158"></a><span class="lineno">  158</span>&#160;    }</div>
<div class="line"><a name="l00159"></a><span class="lineno">  159</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0x0F0F0F0F)</div>
<div class="line"><a name="l00160"></a><span class="lineno">  160</span>&#160;    {</div>
<div class="line"><a name="l00161"></a><span class="lineno">  161</span>&#160;        bits &amp;= 0x0F0F0F0F;</div>
<div class="line"><a name="l00162"></a><span class="lineno">  162</span>&#160;        i -= 4;</div>
<div class="line"><a name="l00163"></a><span class="lineno">  163</span>&#160;    }</div>
<div class="line"><a name="l00164"></a><span class="lineno">  164</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0x33333333)</div>
<div class="line"><a name="l00165"></a><span class="lineno">  165</span>&#160;    {</div>
<div class="line"><a name="l00166"></a><span class="lineno">  166</span>&#160;        bits &amp;= 0x33333333;</div>
<div class="line"><a name="l00167"></a><span class="lineno">  167</span>&#160;        i -= 2;</div>
<div class="line"><a name="l00168"></a><span class="lineno">  168</span>&#160;    }</div>
<div class="line"><a name="l00169"></a><span class="lineno">  169</span>&#160;    <span class="keywordflow">if</span> (bits &amp; 0x55555555)</div>
<div class="line"><a name="l00170"></a><span class="lineno">  170</span>&#160;    {</div>
<div class="line"><a name="l00171"></a><span class="lineno">  171</span>&#160;        bits &amp;= 0x55555555;</div>
<div class="line"><a name="l00172"></a><span class="lineno">  172</span>&#160;        i -= 1;</div>
<div class="line"><a name="l00173"></a><span class="lineno">  173</span>&#160;    }</div>
<div class="line"><a name="l00174"></a><span class="lineno">  174</span>&#160;    <span class="keywordflow">return</span> i;</div>
<div class="line"><a name="l00175"></a><span class="lineno">  175</span>&#160;}</div>
<div class="line"><a name="l00176"></a><span class="lineno">  176</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00177"></a><span class="lineno">  177</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00178"></a><span class="lineno">  178</span>&#160;<span class="preprocessor"></span></div>
<div class="line"><a name="l00179"></a><span class="lineno">  179</span>&#160;<span class="comment">/* N.B. It is tempting to use look-up tables for A-law and u-law conversion.</span></div>
<div class="line"><a name="l00180"></a><span class="lineno">  180</span>&#160;<span class="comment"> *      However, you should consider the cache footprint.</span></div>
<div class="line"><a name="l00181"></a><span class="lineno">  181</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00182"></a><span class="lineno">  182</span>&#160;<span class="comment"> *      A 64K byte table for linear to x-law and a 512 byte table for x-law to</span></div>
<div class="line"><a name="l00183"></a><span class="lineno">  183</span>&#160;<span class="comment"> *      linear sound like peanuts these days, and shouldn&#39;t an array lookup be</span></div>
<div class="line"><a name="l00184"></a><span class="lineno">  184</span>&#160;<span class="comment"> *      real fast? No! When the cache sloshes as badly as this one will, a tight</span></div>
<div class="line"><a name="l00185"></a><span class="lineno">  185</span>&#160;<span class="comment"> *      calculation may be better. The messiest part is normally finding the</span></div>
<div class="line"><a name="l00186"></a><span class="lineno">  186</span>&#160;<span class="comment"> *      segment, but a little inline assembly can fix that on an i386, x86_64 and</span></div>
<div class="line"><a name="l00187"></a><span class="lineno">  187</span>&#160;<span class="comment"> *      many other modern processors.</span></div>
<div class="line"><a name="l00188"></a><span class="lineno">  188</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00189"></a><span class="lineno">  189</span>&#160; </div>
<div class="line"><a name="l00190"></a><span class="lineno">  190</span>&#160;<span class="comment">/*</span></div>
<div class="line"><a name="l00191"></a><span class="lineno">  191</span>&#160;<span class="comment"> * Mu-law is basically as follows:</span></div>
<div class="line"><a name="l00192"></a><span class="lineno">  192</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00193"></a><span class="lineno">  193</span>&#160;<span class="comment"> *      Biased Linear Input Code        Compressed Code</span></div>
<div class="line"><a name="l00194"></a><span class="lineno">  194</span>&#160;<span class="comment"> *      ------------------------        ---------------</span></div>
<div class="line"><a name="l00195"></a><span class="lineno">  195</span>&#160;<span class="comment"> *      00000001wxyza                   000wxyz</span></div>
<div class="line"><a name="l00196"></a><span class="lineno">  196</span>&#160;<span class="comment"> *      0000001wxyzab                   001wxyz</span></div>
<div class="line"><a name="l00197"></a><span class="lineno">  197</span>&#160;<span class="comment"> *      000001wxyzabc                   010wxyz</span></div>
<div class="line"><a name="l00198"></a><span class="lineno">  198</span>&#160;<span class="comment"> *      00001wxyzabcd                   011wxyz</span></div>
<div class="line"><a name="l00199"></a><span class="lineno">  199</span>&#160;<span class="comment"> *      0001wxyzabcde                   100wxyz</span></div>
<div class="line"><a name="l00200"></a><span class="lineno">  200</span>&#160;<span class="comment"> *      001wxyzabcdef                   101wxyz</span></div>
<div class="line"><a name="l00201"></a><span class="lineno">  201</span>&#160;<span class="comment"> *      01wxyzabcdefg                   110wxyz</span></div>
<div class="line"><a name="l00202"></a><span class="lineno">  202</span>&#160;<span class="comment"> *      1wxyzabcdefgh                   111wxyz</span></div>
<div class="line"><a name="l00203"></a><span class="lineno">  203</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00204"></a><span class="lineno">  204</span>&#160;<span class="comment"> * Each biased linear code has a leading 1 which identifies the segment</span></div>
<div class="line"><a name="l00205"></a><span class="lineno">  205</span>&#160;<span class="comment"> * number. The value of the segment number is equal to 7 minus the number</span></div>
<div class="line"><a name="l00206"></a><span class="lineno">  206</span>&#160;<span class="comment"> * of leading 0&#39;s. The quantization interval is directly available as the</span></div>
<div class="line"><a name="l00207"></a><span class="lineno">  207</span>&#160;<span class="comment"> * four bits wxyz.  * The trailing bits (a - h) are ignored.</span></div>
<div class="line"><a name="l00208"></a><span class="lineno">  208</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00209"></a><span class="lineno">  209</span>&#160;<span class="comment"> * Ordinarily the complement of the resulting code word is used for</span></div>
<div class="line"><a name="l00210"></a><span class="lineno">  210</span>&#160;<span class="comment"> * transmission, and so the code word is complemented before it is returned.</span></div>
<div class="line"><a name="l00211"></a><span class="lineno">  211</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00212"></a><span class="lineno">  212</span>&#160;<span class="comment"> * For further information see John C. Bellamy&#39;s Digital Telephony, 1982,</span></div>
<div class="line"><a name="l00213"></a><span class="lineno">  213</span>&#160;<span class="comment"> * John Wiley &amp; Sons, pps 98-111 and 472-476.</span></div>
<div class="line"><a name="l00214"></a><span class="lineno">  214</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00215"></a><span class="lineno">  215</span>&#160;</div>
<div class="line"><a name="l00216"></a><span class="lineno">  216</span>&#160;<span class="comment">//#define ULAW_ZEROTRAP                 /* turn on the trap as per the MIL-STD */</span></div>
<div class="line"><a name="l00217"></a><span class="lineno">  217</span>&#160;<span class="preprocessor">#define ULAW_BIAS        0x84           </span><span class="comment">/* Bias for linear code. */</span><span class="preprocessor"></span></div>
<div class="line"><a name="l00218"></a><span class="lineno">  218</span>&#160;<span class="preprocessor"></span><span class="comment"></span></div>
<div class="line"><a name="l00219"></a><span class="lineno">  219</span>&#160;<span class="comment">/*! \brief Encode a linear sample to u-law</span></div>
<div class="line"><a name="l00220"></a><span class="lineno">  220</span>&#160;<span class="comment">    \param linear The sample to encode.</span></div>
<div class="line"><a name="l00221"></a><span class="lineno">  221</span>&#160;<span class="comment">    \return The u-law value.</span></div>
<div class="line"><a name="l00222"></a><span class="lineno">  222</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00223"></a><span class="lineno">  223</span>&#160;<span class="keyword">static</span> APR_INLINE apr_byte_t linear_to_ulaw(<span class="keywordtype">int</span> linear)</div>
<div class="line"><a name="l00224"></a><span class="lineno">  224</span>&#160;{</div>
<div class="line"><a name="l00225"></a><span class="lineno">  225</span>&#160;    apr_byte_t u_val;</div>
<div class="line"><a name="l00226"></a><span class="lineno">  226</span>&#160;    <span class="keywordtype">int</span> mask;</div>
<div class="line"><a name="l00227"></a><span class="lineno">  227</span>&#160;    <span class="keywordtype">int</span> seg;</div>
<div class="line"><a name="l00228"></a><span class="lineno">  228</span>&#160;</div>
<div class="line"><a name="l00229"></a><span class="lineno">  229</span>&#160;    <span class="comment">/* Get the sign and the magnitude of the value. */</span></div>
<div class="line"><a name="l00230"></a><span class="lineno">  230</span>&#160;    <span class="keywordflow">if</span> (linear &lt; 0)</div>
<div class="line"><a name="l00231"></a><span class="lineno">  231</span>&#160;    {</div>
<div class="line"><a name="l00232"></a><span class="lineno">  232</span>&#160;        linear = ULAW_BIAS - linear - 1;</div>
<div class="line"><a name="l00233"></a><span class="lineno">  233</span>&#160;        mask = 0x7F;</div>
<div class="line"><a name="l00234"></a><span class="lineno">  234</span>&#160;    }</div>
<div class="line"><a name="l00235"></a><span class="lineno">  235</span>&#160;    <span class="keywordflow">else</span></div>
<div class="line"><a name="l00236"></a><span class="lineno">  236</span>&#160;    {</div>
<div class="line"><a name="l00237"></a><span class="lineno">  237</span>&#160;        linear = ULAW_BIAS + linear;</div>
<div class="line"><a name="l00238"></a><span class="lineno">  238</span>&#160;        mask = 0xFF;</div>
<div class="line"><a name="l00239"></a><span class="lineno">  239</span>&#160;    }</div>
<div class="line"><a name="l00240"></a><span class="lineno">  240</span>&#160;</div>
<div class="line"><a name="l00241"></a><span class="lineno">  241</span>&#160;    seg = top_bit(linear | 0xFF) - 7;</div>
<div class="line"><a name="l00242"></a><span class="lineno">  242</span>&#160;</div>
<div class="line"><a name="l00243"></a><span class="lineno">  243</span>&#160;    <span class="comment">/*</span></div>
<div class="line"><a name="l00244"></a><span class="lineno">  244</span>&#160;<span class="comment">     * Combine the sign, segment, quantization bits,</span></div>
<div class="line"><a name="l00245"></a><span class="lineno">  245</span>&#160;<span class="comment">     * and complement the code word.</span></div>
<div class="line"><a name="l00246"></a><span class="lineno">  246</span>&#160;<span class="comment">     */</span></div>
<div class="line"><a name="l00247"></a><span class="lineno">  247</span>&#160;    <span class="keywordflow">if</span> (seg &gt;= 8)</div>
<div class="line"><a name="l00248"></a><span class="lineno">  248</span>&#160;        u_val = (apr_byte_t) (0x7F ^ mask);</div>
<div class="line"><a name="l00249"></a><span class="lineno">  249</span>&#160;    <span class="keywordflow">else</span></div>
<div class="line"><a name="l00250"></a><span class="lineno">  250</span>&#160;        u_val = (apr_byte_t) (((seg &lt;&lt; 4) | ((linear &gt;&gt; (seg + 3)) &amp; 0xF)) ^ mask);</div>
<div class="line"><a name="l00251"></a><span class="lineno">  251</span>&#160;<span class="preprocessor">#ifdef ULAW_ZEROTRAP</span></div>
<div class="line"><a name="l00252"></a><span class="lineno">  252</span>&#160;<span class="preprocessor"></span>    <span class="comment">/* Optional ITU trap */</span></div>
<div class="line"><a name="l00253"></a><span class="lineno">  253</span>&#160;    <span class="keywordflow">if</span> (u_val == 0)</div>
<div class="line"><a name="l00254"></a><span class="lineno">  254</span>&#160;        u_val = 0x02;</div>
<div class="line"><a name="l00255"></a><span class="lineno">  255</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00256"></a><span class="lineno">  256</span>&#160;<span class="preprocessor"></span>    <span class="keywordflow">return</span>  u_val;</div>
<div class="line"><a name="l00257"></a><span class="lineno">  257</span>&#160;}</div>
<div class="line"><a name="l00258"></a><span class="lineno">  258</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00259"></a><span class="lineno">  259</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00260"></a><span class="lineno">  260</span>&#160;<span class="comment">/*! \brief Decode an u-law sample to a linear value.</span></div>
<div class="line"><a name="l00261"></a><span class="lineno">  261</span>&#160;<span class="comment">    \param ulaw The u-law sample to decode.</span></div>
<div class="line"><a name="l00262"></a><span class="lineno">  262</span>&#160;<span class="comment">    \return The linear value.</span></div>
<div class="line"><a name="l00263"></a><span class="lineno">  263</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00264"></a><span class="lineno">  264</span>&#160;<span class="keyword">static</span> APR_INLINE apr_int16_t ulaw_to_linear(apr_byte_t ulaw)</div>
<div class="line"><a name="l00265"></a><span class="lineno">  265</span>&#160;{</div>
<div class="line"><a name="l00266"></a><span class="lineno">  266</span>&#160;    <span class="keywordtype">int</span> t;</div>
<div class="line"><a name="l00267"></a><span class="lineno">  267</span>&#160;    </div>
<div class="line"><a name="l00268"></a><span class="lineno">  268</span>&#160;    <span class="comment">/* Complement to obtain normal u-law value. */</span></div>
<div class="line"><a name="l00269"></a><span class="lineno">  269</span>&#160;    ulaw = ~ulaw;</div>
<div class="line"><a name="l00270"></a><span class="lineno">  270</span>&#160;    <span class="comment">/*</span></div>
<div class="line"><a name="l00271"></a><span class="lineno">  271</span>&#160;<span class="comment">     * Extract and bias the quantization bits. Then</span></div>
<div class="line"><a name="l00272"></a><span class="lineno">  272</span>&#160;<span class="comment">     * shift up by the segment number and subtract out the bias.</span></div>
<div class="line"><a name="l00273"></a><span class="lineno">  273</span>&#160;<span class="comment">     */</span></div>
<div class="line"><a name="l00274"></a><span class="lineno">  274</span>&#160;    t = (((ulaw &amp; 0x0F) &lt;&lt; 3) + ULAW_BIAS) &lt;&lt; (((<span class="keywordtype">int</span>) ulaw &amp; 0x70) &gt;&gt; 4);</div>
<div class="line"><a name="l00275"></a><span class="lineno">  275</span>&#160;    <span class="keywordflow">return</span>  (apr_int16_t) ((ulaw &amp; 0x80)  ?  (ULAW_BIAS - t)  :  (t - ULAW_BIAS));</div>
<div class="line"><a name="l00276"></a><span class="lineno">  276</span>&#160;}</div>
<div class="line"><a name="l00277"></a><span class="lineno">  277</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00278"></a><span class="lineno">  278</span>&#160;</div>
<div class="line"><a name="l00279"></a><span class="lineno">  279</span>&#160;<span class="comment">/*</span></div>
<div class="line"><a name="l00280"></a><span class="lineno">  280</span>&#160;<span class="comment"> * A-law is basically as follows:</span></div>
<div class="line"><a name="l00281"></a><span class="lineno">  281</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00282"></a><span class="lineno">  282</span>&#160;<span class="comment"> *      Linear Input Code        Compressed Code</span></div>
<div class="line"><a name="l00283"></a><span class="lineno">  283</span>&#160;<span class="comment"> *      -----------------        ---------------</span></div>
<div class="line"><a name="l00284"></a><span class="lineno">  284</span>&#160;<span class="comment"> *      0000000wxyza             000wxyz</span></div>
<div class="line"><a name="l00285"></a><span class="lineno">  285</span>&#160;<span class="comment"> *      0000001wxyza             001wxyz</span></div>
<div class="line"><a name="l00286"></a><span class="lineno">  286</span>&#160;<span class="comment"> *      000001wxyzab             010wxyz</span></div>
<div class="line"><a name="l00287"></a><span class="lineno">  287</span>&#160;<span class="comment"> *      00001wxyzabc             011wxyz</span></div>
<div class="line"><a name="l00288"></a><span class="lineno">  288</span>&#160;<span class="comment"> *      0001wxyzabcd             100wxyz</span></div>
<div class="line"><a name="l00289"></a><span class="lineno">  289</span>&#160;<span class="comment"> *      001wxyzabcde             101wxyz</span></div>
<div class="line"><a name="l00290"></a><span class="lineno">  290</span>&#160;<span class="comment"> *      01wxyzabcdef             110wxyz</span></div>
<div class="line"><a name="l00291"></a><span class="lineno">  291</span>&#160;<span class="comment"> *      1wxyzabcdefg             111wxyz</span></div>
<div class="line"><a name="l00292"></a><span class="lineno">  292</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00293"></a><span class="lineno">  293</span>&#160;<span class="comment"> * For further information see John C. Bellamy&#39;s Digital Telephony, 1982,</span></div>
<div class="line"><a name="l00294"></a><span class="lineno">  294</span>&#160;<span class="comment"> * John Wiley &amp; Sons, pps 98-111 and 472-476.</span></div>
<div class="line"><a name="l00295"></a><span class="lineno">  295</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00296"></a><span class="lineno">  296</span>&#160;</div>
<div class="line"><a name="l00297"></a><span class="lineno">  297</span>&#160;<span class="preprocessor">#define ALAW_AMI_MASK       0x55</span></div>
<div class="line"><a name="l00298"></a><span class="lineno">  298</span>&#160;<span class="preprocessor"></span><span class="comment"></span></div>
<div class="line"><a name="l00299"></a><span class="lineno">  299</span>&#160;<span class="comment">/*! \brief Encode a linear sample to A-law</span></div>
<div class="line"><a name="l00300"></a><span class="lineno">  300</span>&#160;<span class="comment">    \param linear The sample to encode.</span></div>
<div class="line"><a name="l00301"></a><span class="lineno">  301</span>&#160;<span class="comment">    \return The A-law value.</span></div>
<div class="line"><a name="l00302"></a><span class="lineno">  302</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00303"></a><span class="lineno">  303</span>&#160;<span class="keyword">static</span> APR_INLINE apr_byte_t linear_to_alaw(<span class="keywordtype">int</span> linear)</div>
<div class="line"><a name="l00304"></a><span class="lineno">  304</span>&#160;{</div>
<div class="line"><a name="l00305"></a><span class="lineno">  305</span>&#160;    <span class="keywordtype">int</span> mask;</div>
<div class="line"><a name="l00306"></a><span class="lineno">  306</span>&#160;    <span class="keywordtype">int</span> seg;</div>
<div class="line"><a name="l00307"></a><span class="lineno">  307</span>&#160;    </div>
<div class="line"><a name="l00308"></a><span class="lineno">  308</span>&#160;    <span class="keywordflow">if</span> (linear &gt;= 0)</div>
<div class="line"><a name="l00309"></a><span class="lineno">  309</span>&#160;    {</div>
<div class="line"><a name="l00310"></a><span class="lineno">  310</span>&#160;        <span class="comment">/* Sign (bit 7) bit = 1 */</span></div>
<div class="line"><a name="l00311"></a><span class="lineno">  311</span>&#160;        mask = ALAW_AMI_MASK | 0x80;</div>
<div class="line"><a name="l00312"></a><span class="lineno">  312</span>&#160;    }</div>
<div class="line"><a name="l00313"></a><span class="lineno">  313</span>&#160;    <span class="keywordflow">else</span></div>
<div class="line"><a name="l00314"></a><span class="lineno">  314</span>&#160;    {</div>
<div class="line"><a name="l00315"></a><span class="lineno">  315</span>&#160;        <span class="comment">/* Sign (bit 7) bit = 0 */</span></div>
<div class="line"><a name="l00316"></a><span class="lineno">  316</span>&#160;        mask = ALAW_AMI_MASK;</div>
<div class="line"><a name="l00317"></a><span class="lineno">  317</span>&#160;        linear = -linear - 1;</div>
<div class="line"><a name="l00318"></a><span class="lineno">  318</span>&#160;    }</div>
<div class="line"><a name="l00319"></a><span class="lineno">  319</span>&#160;</div>
<div class="line"><a name="l00320"></a><span class="lineno">  320</span>&#160;    <span class="comment">/* Convert the scaled magnitude to segment number. */</span></div>
<div class="line"><a name="l00321"></a><span class="lineno">  321</span>&#160;    seg = top_bit(linear | 0xFF) - 7;</div>
<div class="line"><a name="l00322"></a><span class="lineno">  322</span>&#160;    <span class="keywordflow">if</span> (seg &gt;= 8)</div>
<div class="line"><a name="l00323"></a><span class="lineno">  323</span>&#160;    {</div>
<div class="line"><a name="l00324"></a><span class="lineno">  324</span>&#160;        <span class="keywordflow">if</span> (linear &gt;= 0)</div>
<div class="line"><a name="l00325"></a><span class="lineno">  325</span>&#160;        {</div>
<div class="line"><a name="l00326"></a><span class="lineno">  326</span>&#160;            <span class="comment">/* Out of range. Return maximum value. */</span></div>
<div class="line"><a name="l00327"></a><span class="lineno">  327</span>&#160;            <span class="keywordflow">return</span> (apr_byte_t) (0x7F ^ mask);</div>
<div class="line"><a name="l00328"></a><span class="lineno">  328</span>&#160;        }</div>
<div class="line"><a name="l00329"></a><span class="lineno">  329</span>&#160;<span class="preprocessor">#if 0 </span><span class="comment">/* This code is no longer reachable, since linear must be at least 0.  */</span><span class="preprocessor"></span></div>
<div class="line"><a name="l00330"></a><span class="lineno">  330</span>&#160;<span class="preprocessor"></span>        <span class="comment">/* We must be just a tiny step below zero */</span></div>
<div class="line"><a name="l00331"></a><span class="lineno">  331</span>&#160;        <span class="keywordflow">return</span> (apr_byte_t) (0x00 ^ mask);</div>
<div class="line"><a name="l00332"></a><span class="lineno">  332</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00333"></a><span class="lineno">  333</span>&#160;<span class="preprocessor"></span>    }</div>
<div class="line"><a name="l00334"></a><span class="lineno">  334</span>&#160;    <span class="comment">/* Combine the sign, segment, and quantization bits. */</span></div>
<div class="line"><a name="l00335"></a><span class="lineno">  335</span>&#160;    <span class="keywordflow">return</span> (apr_byte_t) (((seg &lt;&lt; 4) | ((linear &gt;&gt; ((seg)  ?  (seg + 3)  :  4)) &amp; 0x0F)) ^ mask);</div>
<div class="line"><a name="l00336"></a><span class="lineno">  336</span>&#160;}</div>
<div class="line"><a name="l00337"></a><span class="lineno">  337</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00338"></a><span class="lineno">  338</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00339"></a><span class="lineno">  339</span>&#160;<span class="comment">/*! \brief Decode an A-law sample to a linear value.</span></div>
<div class="line"><a name="l00340"></a><span class="lineno">  340</span>&#160;<span class="comment">    \param alaw The A-law sample to decode.</span></div>
<div class="line"><a name="l00341"></a><span class="lineno">  341</span>&#160;<span class="comment">    \return The linear value.</span></div>
<div class="line"><a name="l00342"></a><span class="lineno">  342</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00343"></a><span class="lineno">  343</span>&#160;<span class="keyword">static</span> APR_INLINE apr_int16_t alaw_to_linear(apr_byte_t alaw)</div>
<div class="line"><a name="l00344"></a><span class="lineno">  344</span>&#160;{</div>
<div class="line"><a name="l00345"></a><span class="lineno">  345</span>&#160;    <span class="keywordtype">int</span> i;</div>
<div class="line"><a name="l00346"></a><span class="lineno">  346</span>&#160;    <span class="keywordtype">int</span> seg;</div>
<div class="line"><a name="l00347"></a><span class="lineno">  347</span>&#160;</div>
<div class="line"><a name="l00348"></a><span class="lineno">  348</span>&#160;    alaw ^= ALAW_AMI_MASK;</div>
<div class="line"><a name="l00349"></a><span class="lineno">  349</span>&#160;    i = ((alaw &amp; 0x0F) &lt;&lt; 4);</div>
<div class="line"><a name="l00350"></a><span class="lineno">  350</span>&#160;    seg = (((int) alaw &amp; 0x70) &gt;&gt; 4);</div>
<div class="line"><a name="l00351"></a><span class="lineno">  351</span>&#160;    <span class="keywordflow">if</span> (seg)</div>
<div class="line"><a name="l00352"></a><span class="lineno">  352</span>&#160;        i = (i + 0x108) &lt;&lt; (seg - 1);</div>
<div class="line"><a name="l00353"></a><span class="lineno">  353</span>&#160;    <span class="keywordflow">else</span></div>
<div class="line"><a name="l00354"></a><span class="lineno">  354</span>&#160;        i += 8;</div>
<div class="line"><a name="l00355"></a><span class="lineno">  355</span>&#160;    <span class="keywordflow">return</span> (apr_int16_t) ((alaw &amp; 0x80)  ?  i  :  -i);</div>
<div class="line"><a name="l00356"></a><span class="lineno">  356</span>&#160;}</div>
<div class="line"><a name="l00357"></a><span class="lineno">  357</span>&#160;<span class="comment">/*- End of function --------------------------------------------------------*/</span></div>
<div class="line"><a name="l00358"></a><span class="lineno">  358</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00359"></a><span class="lineno">  359</span>&#160;<span class="comment">/*! \brief Transcode from A-law to u-law, using the procedure defined in G.711.</span></div>
<div class="line"><a name="l00360"></a><span class="lineno">  360</span>&#160;<span class="comment">    \param alaw The A-law sample to transcode.</span></div>
<div class="line"><a name="l00361"></a><span class="lineno">  361</span>&#160;<span class="comment">    \return The best matching u-law value.</span></div>
<div class="line"><a name="l00362"></a><span class="lineno">  362</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00363"></a><span class="lineno">  363</span>&#160;apr_byte_t <a class="code" href="g711_8h.html#a37decc9d4106a76d0dae727d930f9ef8">alaw_to_ulaw</a>(apr_byte_t alaw);</div>
<div class="line"><a name="l00364"></a><span class="lineno">  364</span>&#160;<span class="comment"></span></div>
<div class="line"><a name="l00365"></a><span class="lineno">  365</span>&#160;<span class="comment">/*! \brief Transcode from u-law to A-law, using the procedure defined in G.711.</span></div>
<div class="line"><a name="l00366"></a><span class="lineno">  366</span>&#160;<span class="comment">    \param alaw The u-law sample to transcode.</span></div>
<div class="line"><a name="l00367"></a><span class="lineno">  367</span>&#160;<span class="comment">    \return The best matching A-law value.</span></div>
<div class="line"><a name="l00368"></a><span class="lineno">  368</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00369"></a><span class="lineno">  369</span>&#160;apr_byte_t <a class="code" href="g711_8h.html#a73c9eb0057d139a28a4ae58e7491b280">ulaw_to_alaw</a>(apr_byte_t ulaw);</div>
<div class="line"><a name="l00370"></a><span class="lineno">  370</span>&#160;</div>
<div class="line"><a name="l00371"></a><span class="lineno">  371</span>&#160;<a class="code" href="apt_8h.html#a432919823b38eb7e2b6fa2b544fb1644">APT_END_EXTERN_C</a></div>
<div class="line"><a name="l00372"></a><span class="lineno">  372</span>&#160;</div>
<div class="line"><a name="l00373"></a><span class="lineno">  373</span>&#160;<span class="preprocessor">#endif </span><span class="comment">/* MPF_G711_H */</span><span class="preprocessor"></span></div>
<div class="line"><a name="l00374"></a><span class="lineno">  374</span>&#160;<span class="preprocessor"></span><span class="comment">/*- End of file ------------------------------------------------------------*/</span></div>
<div class="ttc" id="apt_8h_html_a432919823b38eb7e2b6fa2b544fb1644"><div class="ttname"><a href="apt_8h.html#a432919823b38eb7e2b6fa2b544fb1644">APT_END_EXTERN_C</a></div><div class="ttdeci">#define APT_END_EXTERN_C</div><div class="ttdef"><b>Definition:</b> apt.h:38</div></div>
<div class="ttc" id="g711_8h_html_a73c9eb0057d139a28a4ae58e7491b280"><div class="ttname"><a href="g711_8h.html#a73c9eb0057d139a28a4ae58e7491b280">ulaw_to_alaw</a></div><div class="ttdeci">apr_byte_t ulaw_to_alaw(apr_byte_t ulaw)</div><div class="ttdoc">Transcode from u-law to A-law, using the procedure defined in G.711. </div></div>
<div class="ttc" id="apt_8h_html_ad3d792bfc75893affad257781ea46e55"><div class="ttname"><a href="apt_8h.html#ad3d792bfc75893affad257781ea46e55">APT_BEGIN_EXTERN_C</a></div><div class="ttdeci">#define APT_BEGIN_EXTERN_C</div><div class="ttdef"><b>Definition:</b> apt.h:36</div></div>
<div class="ttc" id="mpf_8h_html"><div class="ttname"><a href="mpf_8h.html">mpf.h</a></div><div class="ttdoc">Media Processing Framework Definitions. </div></div>
<div class="ttc" id="g711_8h_html_a37decc9d4106a76d0dae727d930f9ef8"><div class="ttname"><a href="g711_8h.html#a37decc9d4106a76d0dae727d930f9ef8">alaw_to_ulaw</a></div><div class="ttdeci">apr_byte_t alaw_to_ulaw(apr_byte_t alaw)</div><div class="ttdoc">Transcode from A-law to u-law, using the procedure defined in G.711. </div></div>
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